<div class="form-group">
    <select name="employe" class="combobox form-control" ng-model="selected.id" my-combobox required>
        <option value="" ng-selected="!selected.id">Select an employe</option>
        <option ng-repeat="employe in staff" value="{{employe.id}}"
                ng-selected="selected.id == employe.id">{{employe.firstName}} {{employe.lastName}}
        </option>
    </select>
</div>